Montana Resources. Conceptual Plans for Permitting Continued Mining Through May 2016

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1 Montana Resources Conceptual Plans for Permitting Continued Mining Through 2040 May 2016

2 Existing Permit Open pit currently permitted to produce ore in excess of 20 years; Sufficient non ore (waste) rock storage available for 20 year mine plan; Tailings impoundment embankment permitted to 6400 elevation (AMC datum); Maximum operating tailing impoundment water level is 6360 elevation;

3 Tailings impoundment; Current Conditions Current water level elevation 6338; Tailings rise is approximately 5 feet per year; Permitted impoundment water level reached in 2020; Must start embankment construction above 6400 in Amendment to Operating Permits for Continued Mining must be in effect in Amendment will match tailings impoundment with permitted reserves and non ore rock storage.

4 YDTI Embankment Construction: Concepts

5 Existing 6400 Embankment General Arrangement Aerial Photograph: June 2013 Reclaim Pond Moulton Road West Embankment Tailings beach North South Embankment East West Embankment Berkeley Pit Montana Resources 5

6 Embankment Raise Concepts Typical Embankment N S Section 6600 Downstream Construction: Free draining waste rock 6400 Existing downstream construction: Free draining waste rock zone Existing Tailings

7 Embankment Raise Concepts Embankment Configuration Typical East West Section 6500 elevation crest NEW Waste Rock (free draining) Reclaim pond ~ 2500 ft NEW Tailings EXISTING Waste Rock (free draining) EXISTING Tailings

8 Embankment Design Concepts West Embankment Construction Section Moulton Road > 800 ft 6500 ft elevation crest Water drains to pond ~ 2500 ft Engineered Fill (low permeability) NEW Waste Rock (free draining) NEW Tailings Toe Drain Montana Resources 8

9 Embankment Design Concepts Embankment Extension General Arrangement Toe Drain Water pumps back into TSF Water pumps back into TSF Contingency Pod Embankment Crest Contingency Pod Montana Resources 9

10 Embankment Design Concepts Embankment Extension General Arrangement Toe Drain Water pumps back into TSF Water pumps back into TSF Embankment Crest Montana Resources 10

11 Proposed 6500 Embankment Configuration Multiple Spigot Points Existing Embankment Montana Resources 11

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15 Current Activities Topsoil and overburden stripping and stockpiling; Stockpiles located adjacent to Mouton Reservoir Road; Foundation preparation; placement of D1 material in draws. Site investigation: Over 45 test pits and trenches; 14 drillholes SPT, core and packer tests foundation for west embankment; 3 deep angle core holes in area around low point in west ridge water table to understand geologic structure at depth; 7 sonic drill holes through east west embankment to verify foundation strengths; 8 cone penetration holes to verify tailings characteristics. Preparation for construction of toe drain.

16 Tailings Impoundment Permitting Applicant must submit a design document detailing how the facility design will address over 32 specific requirements, including: Analysis showing that the TSF will withstand a 1 in 10,000 year earthquake event or maximum credible earthquake, whichever is larger; Design criteria to manage the probable maximum flood event; Design document must be reviewed by a panel of three independent experts.

17 Tailings Impoundment Permitting The independent experts have been selected and approved by MDEQ: Dr. Dirk van Zyl, PE Professor Geotechnical Engineering, UBC Dr. Leslie Smith Professor Hydrogeology, UBC James R. Swaisgood, PE, PG All three experts must sign design document prior to submittal to MDEQ. MR s Engineer of Record is Ken Brouwer, Knight Piésold Ltd.

18 Permit Schedule Submit permit application Q Submit design document Q MDEQ declare the application complete and compliant and issue draft permit Q Initiate MEPA review Q Select MEPA contractor Public scoping comments public meeting Draft MEPA document Public comment public meeting Final MEPA document Issue Record of Decision and final permit Q2 2018

19 Berkeley Pit Alternatives RoD for BMFOU already issued; CD for BMFOU already signed; 14 years of storage in Pit; Would need to operate pit and YDTI concurrently for an extended period of time; Significant technical and logistical challenges.

20 Community Engagement Employees Moulton Road Residents Montana Standard City Commissioners Major Employers Group State Legislative Delegation Federal Legislators Butte Local Development MERDI School Board MDEQ Butte Chief Executive Butte Planning Director Lt Governor Chamber of Commerce Butte Kwanis Butte Public Works Director